Method and machine for producing cartons of cigarettes

Abstract

A method and machine for producing cartons of cigarettes, each consisting of a number of packets of cigarettes housed inside a box formed from a flat blank divided by yield lines into a number of panels; the carton being formed by feeding the blank along a first path to a prefolding station where the blank is folded substantially in a U, and by transferring the prefolded blank to a loading station where a respective group of packets is fed inside the prefolded blank, and is pushed further, along a further path, so as to feed the blank and respective group of packets into a folding channel for closing the box.

We claim: 
     
       1. A method of producing cartons of cigarettes, each carton comprising at least one box formed from a flat blank divided by yield lines into an intermediate panel, and a first and second lateral panel on either side of the intermediate panel; the method comprising the steps of feeding in succession the flat blanks to a prefolding station; arresting each blank in the prefolding station with said intermediate panel facing an inlet of a folding cavity having a substantially U-shaped cross section;   exerting a thrust on, in a first direction substantially perpendicular to, the intermediate panel and said inlet, so as to insert the blank inside the cavity and fold the two lateral panels in a U about the intermediate panel to form a prefolded blank;   extracting the prefolded blank from the cavity via conveying means in a second direction substantially perpendicular to said first direction and parallel to said panels inside said cavity;   feeding the prefolded blank by means of said conveying means along a given path to a loading station; and   pairing each said blank in the loading station with a respective group of packets fed to the loading station via first supply means.   
     
     
       2. A method as claimed in claim 1, wherein said path extends, at least partly, in said second direction. 
     
     
       3. A method as claimed in claim 1, wherein each said prefolded blank is fed by said conveying means to said loading station with its intermediate panel facing the inlet of a folding channel, and with its concavity facing said first supply means; the first supply means being activated so as to feed said group of packets into contact with the intermediate panel and into the folding channel together with the prefolded blank, so as to close said box. 
     
     
       4. A method as claimed in claim 1, wherein each blank is inserted inside said cavity by push means moving reciprocatingly in said first direction; said thrust means being secured contacting said intermediate panel prior to inserting the blank inside the cavity. 
     
     
       5. A method as claimed in claim 1, further comprising the step of folding squarely at least one of the two lateral panels in relation to the intermediate panel as the relevant blank is inserted inside the cavity. 
     
     
       6. A method as claimed in claim 1, inside the cavity, at least one of the two lateral panels is so folded as to be positioned obliquely in relation to, and to form an obtuse angle with, the intermediate panel. 
     
     
       7. A method as claimed in claim 6, further comprising the step of folding a longitudinal tab on the obliquely positioned panel of the blank squarely in relation to the obliquely positioned panel at the prefolding station; said obtuse angle being such that the projection of said folded longitudinal tab onto the plane of said intermediate panel lies outwards of the intermediate panel. 
     
     
       8. A machine for producing cartons of cigarettes, each comprising at least one box formed from a flat blank divided by yield lines into an intermediate panel, and a first and second lateral panel on either side of the intermediate panel; said machine comprising a loading station;   first supply means for successively feeding groups of packets of cigarettes to the loading station, and pairing them with a respective blank   a station for prefolding said blanks;   conveying means for successively transferring the prefolded blanks to said loading station;   said prefolding station comprising a folding cavity with a substantially U-shaped cross section extending along a longitudinal axis, the folding station comprising stop means for arresting each said flat blank with its intermediate panel facing the inlet of said cavity;   and push means moving in a thrust direction perpendicular to said intermediate panel, for engaging the intermediate panel, and inserting the blank inside the cavity so as to fold the two lateral panels in a U about the intermediate panel to form a prefolded blank;   said conveying means cooperating with said prefolding station, for extracting each prefolded blank from said cavity, and feeding it to said loading station, said extracting and feeding being along a given path in a feed direction substantially perpendicular to said thrust direction and parallel to said axis and said panels inside said cavity.   
     
     
       9. A machine as claimed in claim 8, wherein said path extends, at least partly, in said feed direction 
     
     
       10. A machine as claimed in claim 8, further comprising a folding channel having an inlet at the loading station and designed to successively receive said blanks partially folded about respective said groups of packets, and to finish-fold the blanks for forming respective said boxes; said conveying means being designed to feed each blank into the loading station with the intermediate panel facing the inlet of said folding channel, and with its concavity facing said first supply means.   
     
     
       11. A machine as claimed in claim 8, wherein said conveying means at least partly define a surface of said cavity. 
     
     
       12. A machine as claimed in claim 8, wherein the prefolding and loading stations are aligned along said path, which is at least partly defined by said conveying means; said cavity presenting an end surface parallel to said path and perpendicular to said thrust direction.   
     
     
       13. A machine as claimed in claim 12, wherein said cavity is defined by two lateral surfaces on either side of the end surface; at least one of the two lateral surfaces being substantially perpendicular to the end surface.   
     
     
       14. A machine as claimed in claim 13, wherein said cavity is defined by two lateral surfaces on either side of the end surface; at least one of the two lateral surfaces being oblique in relation to, and forming an obtuse angle with, the end surface.   
     
     
       15. A machine as claimed in claim 13, wherein said conveying means comprise a suction belt having a transportation branch extending through the prefolding station and the loading station along said path; said transportation branch at least partly defining one of said two lateral surfaces of said cavity.   
     
     
       16. A machine as claimed in claim 8, wherein said push means are adapted to move in said thrust direction between a first position wherein they extend outside said cavity, and a second position wherein they at least partly engage the cavity; said push means comprising retaining means for releasably securing said intermediate panel to the push means as the push means are moved, in use, from said first to said second position.   
     
     
       17. A machine as claimed in claim 16, wherein said push means comprise a folding head having an outer shape substantially complementary to that of said cavity; said head comprising, on the side facing the cavity, a flat surface parallel to the end surface of said cavity;   and said retaining means comprising a suction device communicating externally via said flat surface of said head.   
     
     
       18. A machine as claimed in claim 8, further comprising folding means for folding a tab on one of the two lateral panels of the blank substantially squarely towards the other of the two lateral panels.